Retroreflective materials have been developed for use in a variety of applications, including road signs, license plates, footwear, and clothing patches. Retroreflective materials are often used as high visibility trim materials in clothing to increase the visibility of the wearer. For example, retroreflective materials are often added to protective garments worn by firefighters, rescue personnel, EMS technicians, and the like.
Retroreflective materials can be particularly useful to increase the visibility of fire and rescue personnel during nighttime and twilight hours. In some situations, however, when firefighter garments are exposed to extreme temperatures during a fire, some impermeable or semi-permeable retroreflective materials may contribute to accumulation of heat and/or fluids inside the garment. Under certain conditions, the trapped heat can result in discomfort or even injury to the skin of a firefighter.
In particular, moisture that has collected under impermeable or semi-permeable retroreflective material may expand or vaporize rapidly when the garment is exposed to extreme temperatures from a fire. If the expanded moisture is unable to quickly escape, the firefighter can be exposed to harmful temperatures. Impermeable or semi-permeable materials on the outside of the garment may constrain the rapid escape of heated moisture vapors, allowing the vapors to be directed toward the firefighter's skin. In some cases, this can result in steam burns or other thermal injury to the skin.
Conventional retroreflective materials, including some perforated retroreflective materials, generally exhibit this phenomenon. Such conventional perforated retroreflective materials include standard retroreflective trim having needle punched holes, laser punched holes, slits, or relatively large holes made with a paper punch. Further, perforating retroreflective materials to make them permeable removes a substantial portion of the retroreflective material, thereby potentially decreasing the conspicuity of the material.